This interactive workbook aims at providing an overview of data sources that are potentially relevant for the analysis of economic, social and ecological dynamics in the area concerned by the creation of the Makay protected area.
Working environment
We use R and a series of packages dedicated to spatial data and analysis.
Code
library(aws.s3)library(tidyverse) # toolkit for data manipulationlibrary(geodata) # to get municipalitieslibrary(sf) # to handle spatial data (vectors)library(terra) # to handle patial data (rasters)library(mapme.biodiversity) # to compute spatial indicatorslibrary(tmap) # nice mapslibrary(zoo) # time serieslibrary(units) # ensures units are rightlibrary(future) # to parallelize computationslibrary(exactextractr) # engine for mapme.biodiversitylibrary(SPEI) # to compute rainfall
Makay protected area
We load the Makay protected area boundaries.
Code
makay_ap <-st_read("data/Makay_wgs84.geojson", quiet =TRUE) %>%rename(Statut = SOURCETHM) %>%mutate(Statut =recode(Statut, "zone tampon"="Zone tampon"))# Fist we dissolve the different areasmakay_union <- makay_ap %>%st_union() %>%st_sf() %>%st_make_valid()# Draw maptmap_mode("view")tm_shape(makay_ap) +tm_polygons(col ="Statut", alpha =0.5) +tm_shape(makay_union) +tm_borders(col ="red") +tm_add_legend(type ="fill", col ="red", labels ="Limite externe") +tm_basemap("OpenStreetMap")
Makay protected area (source: Auréa?)
The protected area is composted of five polygons with different status: four polygons are cores, and one polygon is a buffer area.
Administrative areas
We will now select all municipalities located within a 20km distance from the outer border of the Makay protected area (core or buffer zone).
There are 13 municipalities that directly overlap with Makay: Tandrano, Beroroha, Fanjakana, Mandronarivo, Marerano, Sakena, Tanamary, Ambia, Ankilizato, Beronono, Malaimbandy, Mandabe, Tsimazava. There are 4 municipalities that do not directly overlap with Makay PA but are located within a 20 km radius from Makay PA: Mandrosonoro, Fitampito, Behisatra, Beharona.
Rainfall
We use the CHIRPS data from NASA to estimate 3 day average rainfall on the Makay protected area.The source data has a spatial resolution of 0.05° (about 5km). We compute the data using the package mapme.biodiversity (Görgen and Bhandari 2023).
Code
# We group Makay PA zones and communes to have an object with all areas of interest# We keep only one common field "name"aoi <-bind_rows(filter(makay_ap, Statut =="Zone tampon"),filter(makay_ap, Statut =="Noyau dur") %>%mutate(Statut =paste0(Statut, "_", 1:4))) %>%select(name = Statut) %>%bind_rows(mutate(makay_union, name ="Ensemble")) %>%mutate(name =paste0("AP Makay : ", name)) %>%bind_rows(select(muni_around_makay, name = Nom_commune)) %>%st_cast("POLYGON")# we use parallel computing to reduce processing timeplan(multisession, workers =8)# Reference portfolio (chirps data was loaded at startup)aoi <-init_portfolio(aoi, years =1990:2020,outdir ="data") aoi_1 <-s3read_using(FUN = read_rds, object ="partage/makay/aoi_1.rds",bucket ="fbedecarrats", opts =list("region"=""))if (!exists("aoi_1")) { aoi <- aoi %>%get_resources("chirps")# Compute precipitation aoi_1 <- aoi %>%calc_indicators("precipitation_chirps",engine ="exactextract",scales_spi =3,spi_prev_years =8)s3write_using(aoi_1, FUN = write_rds, object ="partage/makay/aoi_1.rds",bucket ="fbedecarrats", opts =list("region"=""))}# We compute 3d average precipitationsprecip_3d <- aoi_1 %>%unnest(precipitation_chirps) %>%group_by(name) %>%mutate(rainfall_3d_mean =rollmean(absolute, k =3, fill =NA))# We display precipitations for Makay areaprecip_3d %>%filter(name =="AP Makay : Ensemble") %>%ggplot(aes(x = dates, y = rainfall_3d_mean)) +geom_line()
Rainfalls on Makay PA (source : CHIRPS, 3 day rolling average)
Cyclones
We use the Tropical cyclone best track data (IBTrACS) to get history of cyclone trajectories and cyclone attributes (Knapp et al. 2010), as well as raw code from (Schielein 2023).
Code
if (!file.exists("data/ibtracs/IBTrACS.since1980.list.v04r00.lines.shp")) {dir.create("data/ibtracs")download.file(url ="https://www.ncei.noaa.gov/data/international-best-track-archive-for-climate-stewardship-ibtracs/v04r00/access/shapefile/IBTrACS.since1980.list.v04r00.lines.zip", destfile ="data/ibtracs/ibtracs_lines.zip")unzip("data/ibtracs/ibtracs_lines.zip", exdir ="data/ibtracs")}mada <-gadm("MDG", level=0, path ="data") %>%st_as_sf()# column description is given here: https://www.ncei.noaa.gov/sites/default/files/2021-07/IBTrACS_v04_column_documentation.pdfcyclones <-read_sf("data/ibtracs/IBTrACS.since1980.list.v04r00.lines.shp")# Create a buffer 300km around Madagascarmada_buff <-st_buffer(mada, 300)cyclones$wind_combined <- cyclones %>%select(contains("WIND")) %>%select(-WMO_WIND) %>%st_drop_geometry() %>%rowMeans(., na.rm = T)cyclones_mada <- cyclones %>%st_intersection(mada_buff) %>%select(Season = SEASON, Name = NAME, Winds_in_knots = wind_combined)tm_shape(makay_union) +tm_borders(col ="red") +tm_shape(cyclones_mada) +tm_lines(col ="Season", lwd ="Winds_in_knots", scale =3, palette ="Blues",popup.vars =c("Name", "Season", "Winds in knots"="Winds_in_knots"),legend.format =list(big.mark=""), popup.format =list(big.mark=""))
Cyclone trajectories, dates and intensity (source: IBTrACS)
The map shows that the Makay protected area has been hit by a number of significant cyclones. Most notably, Freddy in 2023 and Bastiraï in 2022, both with winds of around 57 knots (1 knot = 1.825 km/h). Lesser cyclones had hit the area in previous years: Chedza in 2014 (winds around 42 knots), Elita in 2005 (winds around 52 knots).
Fires
This analysis is based on the example produced by Darius Goergen on the Mapme website.
We use here the data for all type of conflicts from ACLED (Armed Conflict Location & Event Data Project (ACLED); www.acleddata.com), accessed on August 17th, 2023. ACLED data records violent events registered between 1997 and today. We spatially filter this data over the period of interest to keep only the occurrences in the 17 municipalities above.
Species occurrences
Use of the GBIF data.
References
Görgen, Darius A., and Om Prakash Bhandari. 2023. “Mapme.biodiversity: Efficient Monitoring of Global Biodiversity Portfolios.”
Knapp, Kenneth R., Michael C. Kruk, David H. Levinson, Howard J. Diamond, and Charles J. Neumann. 2010. “The International Best Track Archive for Climate Stewardship (IBTrACS) Unifying Tropical Cyclone Data.”Bulletin of the American Meteorological Society 91 (3): 363–76.
Schielein, Johannes. 2023. “Mapme.protectedareas: Reproducible Processing and Analysis Routines with r to Assist in Planning Monitoring and Evaluation of Projects to Support PAs Worldwide.”